Add simple example Jupyter notebook (for Binder)

[EricCousineau-TRI]

Towards #126

Preview Link:
https://mybinder.org/v2/gh/EricCousineau-TRI/pygccxml/feature-py-notebook-example?filepath=pygccxml/docs/examples/notebook/example.ipynb

[tom-osika]

Just as a note: this looks good so far. I'll do another review and approve when the todos are gone

[EricCousineau-TRI]

Removed TODO about path stuff (I won't be able to investigate anytime soon).

Briefly trying the JupyterLab setup, but may descope that as well.

[EricCousineau-TRI]

JupyterLab does not work easily; will leave in TODO; breadcrumb commit: 608f224

I think the remaining TODOs can remain as they are.

@tao558 Might you have time to take a look?

[tom-osika]

@EricCousineau-TRI I'll take a look ASAP

[EricCousineau-TRI]

FYI I changed requirements away from use a set literal which is then converted to a list. That operation is redundant when dict/set become order-preserving (Python 3.5, I believe?), and provides information loss in lower Python versions.

[tom-osika]

Other than the one comment looks good. Are you OK with me squashing the commits when merging?

[EricCousineau-TRI]

Are you OK with me squashing the commits when merging?

Yup!

[EricCousineau-TRI]

Please squash-merge if that's an option. If not, I can squash myself since review is done.

[tom-osika]

Thanks @EricCousineau-TRI! Good to finally get this merged.